Fungicidal compositions based on fludioxonil

ABSTRACT

Novel fungicidal compositions for the treatment of phytopathogenic diseases of crop plants and against infestation on propagation stock of plants or on other vegetable material, especially phytopathogenic fungi, and to a method of combating phytopathogenic diseases on crop plants or in post-harvest storage and for seed dressing. The invention relates in particular to the control or prevention of diseases in the post-harvest storage period of harvested fruits. It has now been found that the use of a) 4-(2,2-difluoro-1,3-benzodioxol-7-yl)pyrrole-3-carbonitrile (“fludioxonil”) (The Pesticide Manual, 11th. edition, 1997, 334), component I in association with b) either 2-(thiazol-4-yl)benzimidazol, component IIA (“thiabendazole”) (The Pesticide Manual, 11th. edition, 1997, 701); or 1-(β-allyloxy-2,4-dichlorophenylethyl)imidazole, component IIB (“imizalil”) (The Pesticide Manual, 11th. edition, 1997, 410) is particularly effective in combating or preventing fungal diseases of crop plants. These combinations exhibit synergistic fungicidal activity.

This appl. is a 371 of PCT/EP01/07528 filed Jul. 2, 2001.

The present invention relates to novel fungicidal compositions for thetreatment of phytopathogenic diseases of crop plants and againstinfestation on propagation stock of plants or on other vegetablematerial, especially phytopathogenic fungi, and to a method of combatingphytopathogenic diseases on crop plants or in post-harvest storage andfor seed dressing.

The invention relates in particular to the control or prevention ofdiseases in the post-harvest storage period of harvested fruits.

It has now been found that the use of

a) 4-(2,2-difluoro-1,3-benzodioxol-7-yl)pyrrole-3-carbonitrile(“fludioxonil”) (The Pesticide Manual, 11th. edition, 1997, 334),component I in association with

b) either 2-(thiazol-4-yl)benzimidazol, component IIA (“thiabendazole”)(The Pesticide Manual, 11th. edition, 1997, 701); or

1-(β-allyloxy-2,4-dichlorophenylethyl)imidazole, component IIB(“imazalil”) (The Pesticide Manual, 11th. edition, 1997, 410)

is particularly effective in combating or preventing fungal diseases ofcrop plants. These combinations exhibit synergistic fungicidal activity.

Favorable mixture ratios of the two active ingredients are I:II=20:1 to1:20, preferably I:II=10:1 to 1:10 and 5:1 to 1:5.

The active ingredient combinations I+II according to the invention havevery advantageous properties in the protection of plants and duringpost-harvest storage of fruits against the outbreak of disease.

The active ingredient combinations are effective against phytopathogenicfungi belonging to the following classes: Ascomycetes (e.g. Venturia,Podosphaera, Erysiphe, Monilinia, Sclerotinia, Mycosphaerella,Uncinula); Basidiomycetes (e.g. the genus Hemileia, Rhizoctonia,Tilletia, Puccinia); Fungi imperfecti (e.g. Botrytis, Helminthosporium,Rhynchosporium, Fusarium, Septoria, Cercospora, Alternaria, Penicilliumspp., Pyricularia and Pseudocercosporella herpotrichoides).

With the present active ingredient compositions, the microorganismsappearing on plants or plant parts (fruits, flower, foliage, stems,tubers, roots) of different useful plants can be stopped or destroyed,whereby plant parts growing later also remain free from suchmicroorganisms. They may also be used as post-harvest application or asdressing, or the treatment of plant propagation material, speciallyseeds.

Target crops for the areas of indication disclosed herein comprisewithin the scope of this invention e.g. the following species of plants:cereals (wheat, barley, rye, oats, rice, sorghum and related crops);beet (sugar beet and fodder beet); pomes, stone fruit and soft fruit(apples, pears, plums, peaches, almonds, cherries, strawberries,raspberries and blackberries); leguminous plants (beans, lentils, peas,soybeans); oil plants (rape, mustard, poppy, olives, sunflowers,coconut, castor oil plants, cocoa beans, groundnuts); cucumber plants(marrows, cucumbers, melons); fibre plants (cotton, flax, hemp, jute);citrus fruit (oranges, lemons, grapefruit, mandarins); vegetables(spinach, lettuce, asparagus, cabbages, carrots, onions, tomatoes,potatoes, paprika); lauraceae (avocados, cinnamon, camphor); or plantssuch as maize, tobacco, nuts, coffee, sugar cane, tea, vines, hops,turf, bananas and natural rubber plants, as well as ornamentals(flowers, shrubs, broad-leaved trees and evergreens, such as conifers)and their seeds. This list does not represent any limitation.

The combinations of the present invention may also be used in the areaof protecting technical material against attack of fungi. Technicalareas include wood, paper, leather, constructions, cooling and heatingsystems, ventilation and air conditioning systems, and the like. Thecombinations according the present invention can prevent thedisadvantageous effects such as decay, discoloration or mold.

Throughout this document the expression combination stands for thevarious combinations of the components I and II, e.g. in a single“ready-mix” form, in a combined spray mixture composed from separateformulations of the single active ingredient components, e.g. a“tank-mix”, and in a combined use of the single active ingredients whenapplied in a sequential manner, i.e. one after the other with areasonable short period, e.g. a few hours or days. The order of applyingthe components I and II is not essential for working the presentinvention.

The combinations according to the present invention are particularlyeffective against Botrytis spp., Fusarium spp. and Penicillium spp., inparticular against pathogens of fruits plants such as citrus, pomes,stone fruits and soft fruits and bananas as well as potatoes and thecorresponding fruits during post-harvest storage.

The amount of combination of the invention to be applied, will depend onvarious factors such as the compound employed, the subject of thetreatment (plant, soil, post-harvest, seed), the type of treatment (e.g.spraying, dusting, seed dressing), the purpose of the treatment(prophylactic or therapeutic), the type of fungi to be treated and theapplication time.

It has been found that the use of compounds IIA and IIB in combinationwith the compound of formula I surprisingly and substantially enhancethe effectiveness of the latter against fungi, and vice versa.Additionally, the method of the invention is effective against a widerspectrum of such fungi that can be combated with the active ingredientsof this method, when used solely.

The invention also relates to a method of controlling fungi, whichcomprises treating a site, for example a plant, its locus of growth, orduring post-harvest storage of fruits, that is infested or liable to beinfested by fungi with the active component I and with the activecomponent II in any desired order or simultaneously.

The weight ratio of I:II is so selected as to give a synergisticfungicidal action. The synergistic action of the composition is apparentfrom the fact that the fungicidal action of the composition of I+II isgreater than the sum of the fungicidal actions of I and II.

The method of the invention comprises applying to the plants to betreated or the locus thereof in admixture or separately, a fungicidallyeffective aggregate amount of a compound I and a compound of componentb).

The term locus as used herein is intended to embrace the fields on whichthe treated crop plants are growing, or where the seeds of cultivatedplants are sown, or the place where the seed will be placed into thesoil. The term seed is intended to embrace plant propagating materialsuch as cuttings, seedlings, seeds, germinated or soaked seeds.

The combinations are applied by treating the fungi or the seeds, plantsor materials threatened by fungus attack, or the soil with afungicidally effective amount of the active ingredients.

The novel combinations are extremely effective against phytopathogenicfungi. Some of the have a systemic action and can be used as foliar andsoil fungicides, for post-harvest fruits during storage and for seeddressing.

The agents may be applied before or after infection of the materials,plants, during post-harvest storage of fruits or seeds by the fungi.

When applied to the plants or the post-harvest fruits the compound offormula I is applied at a rate of 10 to 150 g/100 l, particularly 20 to100 g/100 l, e.g. 20, 50, or 100 g/100 l, in association with 10 to 1000g/100 l, particularly 30 to 600 g/100 l, e.g. 30 g/100 l, 40 g/100 l, 75g/100 l, 80 g/100 l, 100 g/100 l, 125 g/100 l, 150 g/100 l, 175 g/100 l,200 g/100 l, 300 g/100 l, 500 g/100 l, depending on the class ofchemical employed as component b). Where the component b) is compoundIIA for example 50 to 200 g a.i./100 l is applied in association withthe compound of formula I. Where the component b) is compound IIB forexample 25 to 200 g a.i./100 l is applied in association with thecompound of formula I. In agricultural practice the application rates ofthe combination depend on the type of effect desired, and range from 5to 1000 g of active ingredient per 100 l.

When the active ingredients are used for treating seed, rates of 0.001to 50 g a.i. per kg, and preferably from 0.01 to 10 g per kg of seed aregenerally sufficient.

The invention also provides fungicidal compositions comprising acompound of formula I and a compound of component b).

The composition of the invention may be employed in any conventionalform, for example in the form of a twin pack, an instant granulate, aflowable or a wettable powder in combination with agriculturallyacceptable adjuvants. Such compositions may be produced in conventionalmanner, e.g. by mixing the active ingredients with appropriate adjuvants(diluents or solvents and optionally other formulating ingredients suchas surfactants).

The term diluent as used herein means any liquid or solid agriculturallyacceptable material including carriers which may be added to the activeconstituents to bring them in an easier or improved applicable form,respectively, to a usable or desirable strength of activity. Suitablesolvents are: aromatic hydrocarbons, preferably the fractions containing8 to 12 carbon atoms, e.g. xylene mixtures or substituted naphthalenes,phthalates, such as dibutyl phthalate or dioctyl phthalate, aliphatichydrocarbons, such as cyclohexane or paraffins, alcohols and glycols andtheir ethers and esters, such as ethanol, ethylene glycol, ethyleneglycol monomethyl or monoethyl ether, ketones, such as cyclohexanone,strongly polar solvents, such as N-methyl-2-pyrrolidone, dimethylsulfoxide or dimethylformamide, as well as vegetable oils or epoxidisedvegetable oils, such as epoxidised coconut oil or soybean oil; or water.The solid carriers used, e.g. for dusts and dispersible powders, arenormally natural mineral fillers, such as calcite, talcum, kaolin,montmorillonite or attapulgite. In order to improve the physicalproperties it is also possible to add highly dispersed silicic acid orhighly dispersed absorbent polymers. Suitable granulated adsorptivecarriers are porous types, for example pumice, broken brick, sepioliteor bentonite, and suitable non-absorbent carriers are, for example,calcite or sand. In addition, a great number of materials of inorganicor organic nature can be used, e.g. especially dolomite or pulverizedplant residues. Depending upon the nature of the compounds of formula Iand component b) to be formulated, suitable surface-active compounds arenon-ionic, cationic and/or anionic surfactants having good emulsifying,dispersing and wetting properties. The term “surfactants” will also beunderstood as comprising mixtures of surfactants. Particularlyadvantageous application-promoting adjuvants are also natural orsynthetic phospholipids of the cephalin and lecithin series, e.g.phosphatidylethanolamine, phosphatidylserine, phosphatidylglycerol andlysolecithin.

Particularly formulations to be applied in spraying forms such as waterdispersible concentrates or wettable powders may contain surfactantssuch as wetting and dispersing agents, e.g. the condensation product offormaldehyde with naphthalene sulphonate, an alkylarylsulphonate, alignin sulphonate, a fatty alkyl sulphate, and ethoxylated alkylphenoland an ethoxylated fatty alcohol.

A seed dressing formulation is applied in a manner known per se to theseeds employing the combination of the invention and a diluent insuitable seed dressing formulation form, e.g. as an aqueous suspensionor in a dry powder form having good adherence to the seeds. Such seeddressing formulations are known in the art. Seed dressing formulationsmay contain the single active ingredients or the combination of activeingredients in encapsulated form, e.g. as slow release capsules ormicrocapsules.

In general, the formulations include from 0.01 to 90% by weight ofactive agent, from 0 to 20% agriculturally acceptable surfactant and 10to 99.99% solid or liquid adjuvant(s), the active agent consisting of atleast the compound of formula I together with a compound of componentb), and optionally other active agents, particularly microbicides orconservatives or the like. Concentrate forms of compositions generallycontain in between about 2 and 80%, preferably between about 5 and 70%by weight of active agent. Application forms of formulation may forexample contain from 0.01 to 20% by weight, preferably from 0.01 to 5%by weight of active agent.

The Examples which follow serve to illustrate the invention, “activeingredient” denoting a mixture of compound I and a compound of componentb) in a specific mixing ratio.

Formulations may be prepared analogously to those described in, forexample, WO 97/33890.

Slow Release Capsule Suspension

28 parts of a combination of the component I and a compound of componentb), or of each of these compounds separately, are mixed with 2 parts ofan aromatic solvent and 7 parts of toluenediisocyanate/polymethylene-polyphenylisocyanate-mixture (8:1). Thismixture is emulsified in a mixture of

1.2 parts of polyvinylalcohol, 0.05 parts of a defoamer and 51.6 partsof water until the desired particle size is achieved. To this emulsion amixture of 2.8 parts

1,6-diaminohexane in 5.3 parts of water is added. The mixture isagitated until the polymerization reaction is completed.

The obtained capsule suspension is stabilized by adding 0.25 parts of athickener and 3 parts of a dispersing agent. The capsule suspensionformulation contains 28% of the active ingredients. The medium capsulediameter is 8-15 microns.

The resulting formulation is applied to seeds as an aqueous suspensionin an apparatus suitable for that purpose.

Seed Dressing Formulation

25 parts of a combination of components I and II, 15 parts ofdialkylphenoxypoly(ethylenoxy)ethanol, 15 parts of fine silica, 44 partsof fine kaolin, 0.5 parts of Rhodamine B as a colorant and 0.5 parts ofXanthan Gum are mixed and ground in a contraplex mill at approx. 10000rpm to an average particle size of below 20 microns. The resultingformulation is applied to the seeds as an aqueous suspension in anapparatus suitable for that purpose.

Whereas commercial products will preferably be formulated asconcentrates, the end user will normally employ dilute formulations.

Biological Examples

A synergistic effect exists whenever the action of an active ingredientcombination is greater than the sum of the actions of the individualcomponents.

The action to be expected E for a given active ingredient combinationobeys the so-called COLBY formula and can be calculated as follows(COLBY, S. R. “Calculating synergistic and antagonistic responses ofherbicide combination”. Weeds, Vol. 15, pages 20-22; 1967):

ppm=milligrams of active ingredient (=a.i.) per litre of spray mixture

X=% action by active ingredient I using p ppm of active ingredient

Y=% action by active ingredient II using q ppm of active ingredient.

According to Colby, the expected (additive) action of active ingredientsI+II using p+q ppm of active ingredient is$E = {X + Y - \frac{X \cdot Y}{100}}$

If the action actually observed (O) is greater than the expected action(E), then the action of the combination is superadditive, i.e. there isa synergistic effect.

Alternatively the synergistic action may also be determined from thedose response curves according to the so-called WADLEY method. With thismethod the efficacy of the a.i. is determined by comparing the degree offungal attack on treated plants with that on untreated, similarlyinoculated and incubated check plants. Each a.i. is tested at 4 to 5concentrations. The dose response curves are used to establish the EC90(i.e. concentration of a.i. providing 90% disease control) of the singlecompounds as well as of the combinations (EC 90_(observed)) The thusexperimentally found values of the mixtures at a given weight ratio arecompared with the values that would have been found were only acomplementary efficacy of the components was present (EC 90(A+B)_(expected)). The EC90 (A+B)_(expected) is calculated according toWadley (Levi et al., EPPO-Bulletin 16, 1986, 651-657):${{EC90}\quad ( {A + B} )_{expected}} = \frac{a + b}{\frac{a}{{EC90}\quad (A)_{observed}} + \frac{b}{{EC90}\quad (B)_{observed}}}$

wherein a and b are the weight ratios of the compounds A and B in themixture and the indexes (A), (B), (A+B) refer to the observed EC 90values of the compounds A, B or the given combination A+B thereof. Theratio EC90 (A+B)_(expected)/EC90 (A+B)_(observed) expresses the factorof interaction (F). In case of synergism, F is >1.

EXAMPLE B-1 Efficacy Against Botrytis cinerea on Apple

In an apple fruit cv. Golden Delicious 3 holes were drilled and eachfilled with 50 μl droplets of the formulated test composition. Two hoursafter application 50 μl of a spore suspension of B. cinerea (4×10⁵conidia/ml) were pipetted on the application sites. After an incubationperiod of 5 days at 20° C. in a growth chamber the % infected fruit areawas determined. The activity was calculated relative to the disease rateon untreated apple fruits. The fungicide interactions in the mixturewere calculated according to Colby.

Results

TABLE 1 Fludioxonil Thiabendazole % activity % activity SF mg a.i./l mga.i./l Ratio observed expected Colby 5 67 2.5 54 0.1 2 25 5 5 12 2.5 101 10 0.5 5 2.5 25 1:10 67 56 1.2 0.1 1 1:10 17 12 1.4 0.1 0.5 1:5  16 72.3 2.5 5 1:2  73 59 1.2 5 5 1:1  100 71 1.4 2.5 2.5 1:1  79 58 1.3

TABLE 2 Fludioxonil Imazalil % activity % activity SF mg a.i./l mga.i./l Ratio observed expected Colby 5 67 0.5 24 0.1 2 25 21 5 0 1 6 0.11 1:10 10 8 1.2 5 25 1:5  82 74 1.1 0.5 1 1:2  33 28 1.2 5 5 1:1  87 671.3

EXAMPLE B-2 Efficacy Against Fusarium on Wheat

A conidia suspension of Fusarium (7×10⁵ conidia/ml) is mixed with theformulated test composition. The mixture is applied into a pouch whichwas previously equipped with a filter paper. After application wheatseeds (cv. Orestis) are sown into then upper fault of the filter paper.The prepared pouches are then incubated for 11 days at approx. 10-18° C.and a relative humidity of 100% with a photo period of 14 hours. Theevaluation is made by assessing the degree of disease occurrence in theform of brown lesions on the roots.

EXAMPLE B-3 Efficacy Against Penicillium on Lemon Fruits

Lemon fruits were inoculated by placing 50 μl spore suspension with 0.1%tween 20 and a density of 500000 spores/ml into each hole (twoholes/fruit) which are prepared by boring the holes into the lemon peelapproximately 1 cm diameter and a depth of 1-1.5 mm. The fruits werestored in covered plastic boxes under light at 20° C. and checked 5-7days after inoculation.

The mixtures according to the invention exhibit good activity in theseexamples.

What is claimed is:
 1. A method of combating phytopathogenic diseasescaused by phytopathogenic fungi, on crop plants or post-harvest fruitswhich comprises applying to the crop plants or the locus thereof beinginfested with said phytopathogenic disease an effective amount of amixture consisting essentially of a)4-(2,2-difluoro-1,3-benzodioxol-7-yl)pyrrole-3-carbonitrile, component Iin association with b) either 2-(thiazol-4-yl)benzimidazol, componentIIA; or 1-(β-allyloxy-2,4-dichlorophenylethyl)imidazole, component IIBwhich synergistically enhances the activity against phytopathogenicdiseases.
 2. A method according to claim 1, wherein b) compound is thecompound IIA.
 3. A method according to claim 1, wherein b) compound isthe compound IIB.
 4. A method according to claim 1, wherein thephytopathogenic fungi belongs to the class of fungi imperfecti.
 5. Amethod according to claim 1, wherein said mixture is applied topost-harvest fruits during post-harvest storage.
 6. A method accordingto claim 1, which comprises applying to the plants, or their locus ofgrowth, or the post-harvest fruits, which are infected or liable to beinfected, a) compound I and b) a compound selected from compound IIA andcompound IIB in any order or simultaneously.
 7. A method according toclaim 1, wherein said crop plant is a plant propagation material.
 8. Amethod according to claim 7, wherein the plant propagation material isseed.
 9. A fungicidal composition comprising a fungicidally effectivecombination of a)4-(2,2-difluoro-1,3-benzodioxol-7-yl)pyrrole-3-carbonitrile, component Iin association with b) either 2-(thiazol-4-yl)benzimidazol, componentIIA; or 1-(β-allyloxy-2,4-dichlorophenylethyl)imidazole, compound IIB,wherein the components are present in amounts which synergisticallyenhances the activity against phytopathogenic diseases.
 10. Acomposition according to claim 9, wherein the weight ratio of a) to b)is between 20:1 and 1:20.
 11. A composition according to claim 9,wherein b) compound is the compound IIA.
 12. A composition according toclaim 9, wherein b) compound is the compound IIB.
 13. A compositionaccording to claim 9, wherein the components a) I and b) II are presentin amounts which synergistically enhance the activity againstphytopathogenic fungi belonging to the class of fungi imperfecti.